Fallopia Adans. (1763) in the family Polygonaceae, consists of around 9 species of annuals, shrubby climbers, and large herbaceous perennials. Fallopia baldschuanica (Regel) Holub, which is shown and described here, is the Russian vine, commonly grown to hide ugly fences and buildings.

Description Climbing shrubs to 5m or more, with twining stems that eventually become slightly woody. The leaves are deciduous, entire, usually heart-shaped. The flowers are small, pink or white, in narrow, branching spikes. There are 5 segments, the outer 3 larger, with keels or wings. Stamens are 8, styles 3; flowers are often male or female in function, with either the stamens or the styles being sterile. Pollination is by perhaps by wind. The fruits are dry and nut-like, triangular in section, usually dark brown or black, and glossy.

Key Recognition Features The climbing stems, heart-shaped leaves, and triangular seeds.

Evolution and Relationships Polygonaceae is a mainly non-woody family that includes such familiar plants as docks (Rumex), buckwheat (Fagopyrum) and rhubarb (Rheum). Other slightly woody genera in the family include the climbing Muehlenbeckia Meissn. and the shrubby Atraphaxis L. from Europe and Central Asia.

Ecology and Geography Fallopia species are found in various habitats from Europe to Japan. Fallopia baldschuanica was first described from Baldschuan, in southern present-day Tajikistan, just north of the Afghan border. Fallopia aubertii (I. Henry) Holub. was described from Kanding in western Sichuan, 3000km to the east, but the 2 species differ in only very minor characteristics.

Comment Fallopia is often included in Polygonum L. or divided between other genera, but is at present recognised as a genus that includes both the mainly climbing species sometimes classed as Bilderdykia Dumort. and the giant, invasive herbaceous perennials previously classed as Reynoutria Houtt. which includes the potent pest Japanese knotweed, Fallopia japonica (Meissn.) Holub.